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Search Results: 1 - 10 of 462662 matches for " Jerry A GRIFFITH "
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The role of landscape pattern analysis in understanding concepts of land cover change


地理学报 , 2004,
Remote Sensing and Mapping of Tamarisk along the Colorado River, USA: A Comparative Use of Summer-Acquired Hyperion, Thematic Mapper and QuickBird Data
Gregory A. Carter,Kelly L. Lucas,Gabriel A. Blossom,Cheryl L. Lassitter,Dan M. Holiday,David S. Mooneyhan,Danielle R. Fastring,Tracy R. Holcombe,Jerry A. Griffith
Remote Sensing , 2009, DOI: 10.3390/rs1030318
Abstract: Tamarisk (Tamarix spp., saltcedar) is a well-known invasive phreatophyte introduced from Asia to North America in the 1800s. This report compares the efficacy of Landsat 5 Thematic Mapper (TM5), QuickBird (QB) and EO-1 Hyperion data in discriminating tamarisk populations near De Beque, Colorado, USA. As a result of highly correlated reflectance among the spectral bands provided by each sensor, relatively standard image analysis methods were employed. Multispectral data at high spatial resolution (QB, 2.5 m Ground Spatial Distance or GSD) proved more effective in tamarisk delineation than either multispectral (TM5) or hyperspectral (Hyperion) data at moderate spatial resolution (30 m GSD).
A comparison of six analytical disease mapping techniques as applied to West Nile Virus in the coterminous United States
Daniel A Griffith
International Journal of Health Geographics , 2005, DOI: 10.1186/1476-072x-4-18
Abstract: West Nile Virus (WNV [1,2]), first isolated in the West Nile District of Uganda in 1937, is a flavivirus transmitted by a mosquito vector, with a general incubation period of 2–14 days following a bite by an infected mosquito, and is closely related to the St. Louis encephalitis virus that also is found in the United States (US). WNV can infect humans, birds, mosquitoes, horses and some other mammals, with mosquitoes becoming infected after feeding on the blood of birds that carry the virus (this virus enters and circulates in a mosquito's bloodstream for a few days before it settles in the insect's salivary glands); of particular concern is that the adult WNV-carrying Culex species of mosquito is able to survive through winters. WNV primarily results in bird mortality, and human and equine encephalitis. In temperate latitudes, West Nile encephalitis cases occur primarily in the late summer or early fall; WNV tends to be carried by less than 1 out of every 100 mosquitoes residing in geographic regions in which it actively circulates. WNV, with its first detected US case on Long Island in 1999, has swiftly diffused across the continental US (Figure 1a and Table 1) as well as elsewhere in the Western Hemisphere. This virus enjoyed a surprisingly rapid rate of diffusion, spreading from the New York City area to nearby localities contagiously, as well as leaping across space in a hierarchical fashion through, for example, bird migration routes (see http://westnilemaps.usgs.gov/ webcite). Although presently a person has a low risk of contracting WNV, many people infected with this virus – more than 16,000 have tested positive to date – tend to experience mild (e.g., flu-like symptoms such as fever, headache, body ache and skin rash) or no symptoms (i.e., never realizing that they have been exposed to WNV), with less than 1% of those infected developing serious illness (e.g., high fever, severe headache, stiff neck, disorientation, tremors, muscle weakness, paralysis and
Disentangling degenerate solutions from primary transit and secondary eclipse spectroscopy of exoplanets
Caitlin A. Griffith
Physics , 2013, DOI: 10.1098/rsta.2013.0086
Abstract: Infrared transmission and emission spectroscopy of exoplanets, recorded from primary transit and secondary eclipse measurements, indicate the presence of the most abundant carbon and oxygen molecular species (H2O, CH4, CO, and CO2) in a few exoplanets. However, efforts to constrain the molecular abundances to within several orders of magnitude are thwarted by the broad range of degenerate solutions that fit the data. Here we explore, with radiative transfer models and analytical approximations, the nature of the degenerate solution sets resulting from the sparse measurements of "hot Jupiter" exoplanets. As demonstrated with simple analytical expressions, primary transit measurements probe roughly 4 atmospheric scale heights at each wavelength band. Derived mixing ratios from these data are highly sensitive to errors in the radius in planet (at a reference pressure), which are approximately a few percent. For example, an uncertainty of 1% in the radius of a 1000 K and H2-based exoplanet with Jupiter's radius and mass, causes an uncertainty of a factor of ~100-10000 in the derived gas mixing ratios. The degree of sensitivity depends on how the line strength increases with the optical depth (i.e. the curve of growth) and the atmospheric scale height. Temperature degeneracies in the solutions of the primary transit data, which manifest their effects through scale height and absorption coefficients, are smaller. We argue that these challenges can be partially surmounted by a combination of selected wavelength sampling of optical and IR measurements and, when possible, the joint analysis of transit and secondary eclipse data of exoplanets.
The Need to Regularise Activities of Illegal Small-Scale Mining in Ghana: A Focus on the Tarkwa-Dunkwa Highway*  [PDF]
Jerry S. Kuma, Jerome A. Yendaw
International Journal of Geosciences (IJG) , 2010, DOI: 10.4236/ijg.2010.13015
Abstract: Southwest Ghana is a major gold producing region. The current high gold price has attracted hundreds of unemployed youth to undertake small-scale mining (SSM). Most of these miners operate illegally even though the SSM law (PNDCL) 218 of 1989 and Act 703 of 2006 define the procedures required for their operation. Some miners have brought their activities to a segment of the western highway that links southwest to central Ghana with serious environmental consequences envisaged. This paper argues that the laws that regulate SSM do not consider the fundamental set-up and concerns of the small-scale miner, hence its inability to be effective. It is therefore proposed that the present requirement that a minimum of 21 hectares is necessary before land can be registered needs re-examination. Secondly, government needs to explore parcels of land and designate the workable areas to miners under a well structured scheme that will also educate these miners about safe and healthy mining methods.
Syzygy Theorems via Comparison of Order Ideals on a Hypersurface
Phillip A. Griffith,Alexandra Seceleanu
Mathematics , 2011,
Abstract: We introduce a weak order ideal property that suffices for establishing the Evans-Griffith Syzygy Theorem. We study this weak order ideal property in settings that allow for comparison between homological algebra over a local ring $R$ versus a hypersurface ring $R/(x^n)$. Consequently we solve some relevant cases of the Evans-Griffith syzygy conjecture over local rings of unramified mixed characteristic $p$, with the case of syzygies of prime ideals of Cohen-Macaulay local rings of unramified mixed characteristic being noted. We reduce the remaining considerations to modules annihilated by $p^s$, $s>0$, that have finite projective dimension over a hypersurface ring.
Effect of Irrigation Method and Non-Uniformity of Irrigation on Potato Performance and Quality  [PDF]
Kamal H. Amer, Abdellateif A. Samak, Jerry L. Hatfield
Journal of Water Resource and Protection (JWARP) , 2016, DOI: 10.4236/jwarp.2016.83024
Abstract: Potato growth, yield, and quality under improved irrigation methods and non-uniformity of their irrigation applications are important to enhance water management in arid regions. A field experiment was conducted in 2014 spring and fall growing seasons using potato (Solanum tuberosum) grown in northern Egypt at Shibin El Kom, Menofia, Egypt to evaluate potato response to furrow or trickle irrigation. A Randomized Split-Plot Design with irrigation method randomly distributed and non-uniformity of irrigation applications evaluated along either irrigation furrow or trickle lateral as dependent variables measured at the 3rd, 13th, 23rd, 33rd, 43rd and 53rd m along the 55 m irrigation line. Traditional (TF) and partial (PF) furrows as well as trickle point (TP) and line (TL) sources were used as irrigation methods. Each treatment was repeated three times. For a 33rd m treatment, seasonal optimum water use by potato was 328, 234, 269 and 292 mm over 118 days in spring and 200, 164, 178 and 186 mm over 122 days in fall under TF, PF, TP and TL irrigation methods, respectively. Potato tuber yield and quality were significantly affected by growing season (S), irrigation method (I) and non-uniformity of irrigation application (U). Tuber yield, total soluble solid (TSS) and leaf area index (LAI) were significantly affected by I and U, and their interaction I * U; harvest index (HI) was not affected by I but U. Except for TSS by S * I and HI by U * I and S * I, results showed no significant differences. Moreover, tuber weight, number and marketable yield were significantly affected by S, I, U and I * U interaction, except medium tuber size and culls by S. A given 33rd treatment under partial furrow and trickle irrigation, relative to that of traditional furrow, enhanced tuber yield and improved quality in both growing seasons. In non-un- iform irrigation application over two growing seasons, potato crop response was developed under varied irrigation methods. Tuber yields were significantly affected in a linear relationship (r2 ≥ 0.75) by either water deficit or excessive water under irrigation methods.
Mapping It Out! A Contemporary View of Burgess's Concentric Ring Model of Urban Growth
Sandra L. Arlinghaus,Daniel A. Griffith
Solstice : Electronic Journal of Geography and Mathematics , 2010,
Estimating Mass of Harvested Asian Seabass Lates calcarifer from Images  [PDF]
Dmitry A. Konovalov, Alzayat Saleh, Jose A. Domingos, Ronald D. White, Dean R. Jerry
World Journal of Engineering and Technology (WJET) , 2018, DOI: 10.4236/wjet.2018.63B003
Total of 1072 Asian seabass or barramundi (Lates calcarifer) were harvested at two different locations in Queensland, Australia. Each fish was digitally photographed and weighed. A subsample of 200 images (100 from each location) were manually segmented to extract the fish-body area (S in cm2), excluding all fins. After scaling the segmented images to 1mm per pixel, the fish mass values (M in grams) were fitted by a single-factor model (M=aS1.5, a=0.1695 )achieving the coefficient of determination (R2) and the Mean Absolute Relative Error (MARE) of R2=0.9819 and MARE=5.1%, respectively. A segmentation Convolutional Neural Network (CNN) was trained on the 200 hand-segmented images, and then applied to the rest of the available images. The CNN predicted fish-body areas were used to fit the mass-area estimation models: the single-factor model, M=aS1.5, a=0.170, R2=0.9819, MARE=5.1%; and the two-factor model, M= aSb, a=0.124, b=0.155, R2=0.9834, MARE=4.5%.
DNA Gene Expression to Study Immunologic Mechanisms for the Long-Term Cure of Malaria in Babies and Children in South-Western Nigeria  [PDF]
Jerry T. Thornthwaite, Akanni E. Olufemi, Ayankunle A. Ademola, O. A. T. Alli
Advances in Biological Chemistry (ABC) , 2019, DOI: 10.4236/abc.2019.92006
Abstract: Malaria infection has been a very serious public health problem in Nigeria and most parts of Africa. Development of antimalarial treatments capable of providing a permanent cure for malaria has been a herculean task for drug researchers. A trial of a novel, proprietary blend formulation (TriantimalTM) in gel caps for children (n = 112) and water-soluble, 18.51 nm diameter, NutraNanoSphereTM encapsulated TriantimalTM drops for babies (19.9 Months ± 8.7 SD, n = 15) was conducted in Osogbo, Nigeria. The enrolled subjects were screened for malaria, treated with TriantimalTM for 16 consecutive days and sera collected on days 0, 5, 10, 16, 30, 60, and 730. Also, 31 of the children donated buffy coat samples for the gene expression studies when sera were collected. The children showed 90.2% parasite-free at 60 days and 85.1% at 730 days. The babies revealed 93.3% parasite-free at 60 days. These data show for the first time a real possibility for a cure of malaria in Nigeria. The one-time, low dose, extended treatment
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